Over recent years, the applications and uses for telephone service have expanded at an accelerated pace. Automated telephone operations have enabled telephone promotions and campaigns that reach vast numbers of telephone lines. Also, expanded telephone operations now serve a variety of apparatus that is foreign to traditional telephonic voice communication, for example, facsimile machines. With the continuing expansion of telephone activity, the number of erroneously placed calls (“wrong numbers”) has greatly increased. Generally, for various reasons, a typical telephone line can be expected to receive many calls that are simply unwanted, perhaps several per day. Such calls not only are an inconvenient annoyance, but also may actually concern or intimidate the recipients, particularly when such calls occur during the night.
Some unwanted telephone calls simply are accidental, for example calls in which the called number is erroneously entered, either manually or automatically. Other unwanted calls are deliberate as in the case of mass calling promotions. Generally, as the numbers of unwanted calls have steadily increased, various solutions have been proposed. For example, some people have adopted a practice of using a telephone answering machine to screen calls. Also, caller identification units are in widespread use for screening. However, in spite of various proposals, the problem continues to exist, perhaps even intensifying. Consequently, a need exists for developments to mitigate the problem of unwanted telephone calls.